Segmented panel mat

ABSTRACT

A lightweight universal panel mat made of plastic or elastomeric material and having a first section that provides a relatively flat surface and provides a frame for receiving a plurality of removable panels that form a working surface within the panel mat. The panel mat includes a second section having geometry that supports the first section. The mats also include first, second, third and fourth sides forming a perimeter of the mat, wherein the first and second sides include upper structures having a sloped lower surface and the third and fourth sides include lower structures having sloped upper surfaces. The sloped surfaces are configured to allow for overlapping with sloped surfaces other like mats for interlocking therewith while forming a generally flat continuous top and bottom surface of the overlapped mats. The mats may be interlocked by a fastening member which fits in aligned openings of the adjacent mats for connection therewith.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/914,386, filed on Oct. 11, 2019, the entirety of which is expressly incorporated herein by reference thereto.

BACKGROUND

The present invention relates to a reusable lightweight panel mat system for the construction of equipment support surfaces and temporary walkways and roadways in areas having poor ground integrity characteristics. More particularly, the present invention relates to a reusable system of durable panel mats which are much lighter than wood or wood/steel mats which can be quickly and easily positioned in a single layer to form equipment support surfaces, walkways or roadways and which can thereafter be easily removed and stored until needed again.

While conventional wood mats provide useful service at a reasonable cost, the wood core can deteriorate over time due to moisture causing gradual rotting and degradation of the wood material. This causes the mat to be discarded, because unlike some of the other materials that are used on the upper and lower layers of the mat, the core cannot be replaced without essentially making an entirely new mat.

Reusable lightweight panel mat systems can be expensive to produce, rent, or purchase and although durable can be subject to damage from the operation of machines or equipment on its working surface. The cost, time, and effort to replace a mat due to damage can be expensive to the operator of the site that is using the panels. A single panel mat can also be heavy to life and move and if damages, may have usable aspects that may be wasted if replaced.

Thus, there is a need for improvement in these types of mat constructions both to provide longer service lives as well as to conserve natural resources and facilitate installation, and these needs are now satisfied by the panel mats of the present invention.

SUMMARY OF THE INVENTION

In accordance with principles of the invention, a lightweight universal panel mat made of plastic or elastomeric material and designed to be interlocked with additional panel mats of similar configurations is provided. The panel mat comprises a first section having an upper surface that forms a peripheral top surface of the panel mat and is relatively flat and provides a receptacle that is adapted to receive one or more removable panels; a second section having geometry that supports the first section; first, second, third and fourth sides forming a perimeter of the mat, wherein, the first and second sides are adjacent and each includes an upper structure that has an upper surface that extends the top surface of the mat and a lower surface that slopes downwardly towards the bottom surface of the mat and the third and fourth sides are adjacent and each includes a lower structure that has a lower surface that extends the bottom surface of the mat and an upper surface that slopes upwardly towards the top surface of the mat. Each upper and lower structure includes at least one opening passing therethrough. The downwardly sloped lower surface of the upper structure and the upwardly sloped upper surface of the lower structure are configured to allow for overlapping with respective lower and upper structures of other like mats when placed adjacent thereto for joining therewith by which the overlapped upper and lower structures form a generally flat continuous top and bottom surface of the overlapped mats and wherein the first and second sections are welded or bonded together to form a unitary panel mat.

In a preferred embodiment, the mat includes one or a plurality of removable panels with the first section forming a frame around the one or more removable panels.

In some embodiments, the first section comprises four sections that are attached together and form a frame that shapes sidewalls for the receptacle.

In some embodiments, the one or more panels are a plurality of removable panels that are locked to each other to thereby form a working surface and the panels are removable from the working structure to be replaced if damaged.

In some embodiments, the panels are removable panels of two different types that interengage. The sidewalls of the receptacle may include protrusions or recesses for joining with mating recesses or protrusions of the removable panels so that the panels can be locked to and secured to the sidewalls of the receptacle or to each other.

The panels preferably have a uniform configuration to facilitate removal and replacement of damaged panels. This can be a rectangular or square shape and a plurality of apertures that are configured to align with adjacent similarly configured panels. Alternatively, it can be an I- or Y-shape with protrusions and recesses for mating with adjacent similarly configured panels.

In some embodiments, the one or more panels comprises an array of removable panels wherein each removable panel comprises a cam that connects to an adjacent removable panel.

In some embodiments, each removable panel comprises a hook that engages a cam when locked.

In some embodiments, each removable panel comprises a protrusion that mates with an adjacent removable panel.

In some embodiments, the removable panels have a rectangular or square shape.

In some embodiments, the receptacle comprises sidewalls and a bottom surface that form an area that fits an array of the panels that are locked to each other to form a working a surface.

A support surface, deck, walkway or roadway comprising one or a plurality of the panel mats disclosed herein can be provided with the mats attached each other. These mats preferably include one or a plurality of panels that are removable when damaged and that are replaced by a like configured panel to extend the service life of the support surface, deck, walkway or roadway. The support surface, deck, walkway or roadway can be one that is constructed for temporary or permanent use.

Each mat typically includes an array of removable panels locked to each other and positioned in the receptacle of each panel mat. Also, the second section can include cells under the first section in an area that forms a frame for the removable panels.

The invention also provides a method of extending the service life of a support surface, deck, walkway or roadway which comprises constructing the support surface, deck, walkway or roadway with a plurality of mats disclosed herein; and replacing any of the removable panels that become damaged to allow continued use of the support surface, deck, walkway or roadway without having to replace an entire mat.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The invention is more fully appreciated upon a review of the appended drawing figures which illustrate the most preferred embodiments of the invention and wherein:

FIG. 1 is a perspective view of a panel mat according to a first embodiment of the present invention showing the top surface of the first section;

FIG. 2 is a perspective view of the mat of FIG. 1 showing a lower surface of the third section;

FIG. 3 is an exploded view of the mat of FIG. 1;

FIG. 4 is an exploded view of the mat of FIG. 2;

FIG. 5 is an illustration of the mat of FIG. 1 wherein the third section is not yet welded to the first and second sections;

FIG. 6 is an illustration of the mat of FIG. 2 wherein the third section is not yet welded to the first and second sections;

FIG. 7 is a perspective view of a panel mat according to a second embodiment of the present invention showing the top surface of the first section;

FIG. 8 is a perspective view of the mat of FIG. 7 showing a lower surface of the third section;

FIG. 9 is a side view of the mat of FIG. 7 showing the upper and lower structures that are configured to facilitate joining or connection to a like configured mat;

FIG. 10 is an illustration of four interconnected mats;

FIG. 11 is an illustration of a mat that is adapted to receive a set of panels;

FIG. 12 is an illustration of a mat that includes an assembled array of panels;

FIG. 13 is an illustration of a mat that is adapted to receive a set of panels (oriented differently than FIG. 10);

FIG. 14 is an illustration of a mat that includes an assembled array of panels;

FIG. 15 is an illustration of a four section frame for the mat;

FIG. 16 is an illustration of an assembled frame;

FIG. 17 is an illustration of a plurality of interconnected mats (each having an array of assembled removable panels)

FIG. 18 is an illustration of a removable panel; and

FIG. 19 is an illustration of a metal frame for a removable panel.

DETAILED DESCRIPTION OF THE INVENTION

Certain terms that are used herein are defined hereinbelow to assist in the understanding of the invention.

The terms “substantially” and “relatively” are used for their ordinary meanings to indicate that the dimensions or configurations are not precise or exact. A skilled artisan can readily determine what tolerances are acceptable to provide a surface that is considered to be flat based upon the size of the panel mats and the type of service that the panel mats are expected to provide. Typically, the terms “substantially” or “relatively” will mean that a surface can vary by as much as an inch or two although in the more preferred embodiments the variance is less than 1 inch.

Additionally, all dimensions recited herein are approximate and can vary by as much as 10% to in some case 25%. In some situations, the term “about” is used to indicate this tolerance. And when the term “about” is used before reciting a range, it is understood that the term is applicable to each recited value in the range. Often, the craftsmanship and engineering procedures that are followed in construction of these mats minimize these tolerances as much as possible or industrially practical.

The present invention relates to improvements to panel mats related to adapted the panel mats to receive “sub panels” that form a working surface of the panel mat. The sub panels, which are generally referred to as removable panels are assembled in a receptacle or recess in the panel mat to from the surface area. The removable panels are connected to each other using mechanical attachments. The removable panels fit together to form a continuous surface subject to small seams where the removable panels abut. If an individual removable panel is damaged (e.g., due to on-the-job use) the damaged removable panel can be removed and replaced without the need to remove or replace other removable panels or the panel mat. The removable panels are adapted to have a mechanism that permits an individual removable mat to be disconnected from adjacent mats and removed from the panel mat. Removable in this context means a panel that has mechanical connectors that can be locked into place and unlocked for removal by hand or a mechanical tool. The following discussion first discussed the structure of panel mats and is followed by a discussion of panel mats having removable panels.

A rectangular panel mat can for example be square or rectangular and be made of plastic or elastomeric material. The panel mat can be made of first and second sections (for two layer mats) or with an additional third section (for three layer mats) which are part of an integral component that is molded to have the desired configuration and features. Typically, the first and second sections are molded together in one operation while the third section is later joined to the mat formed from the first and second sections. Alternatively, a two layer mat can be made from a solid integral plastic or elastomeric component wherein the tabular extensions, openings and slots or recesses are milled or routered into the component top provide the configurations and features. The third section can then be added to the formed mat. Preferably, however, the first and second sections are separately molded and then combined in the desired configurations disclosed herein. To form the panel, the molded first and second sections may be joined together by welding, an adhesive, molding, bonding, or by joining via an interlocking structure. Having each section heated and joined together in a press is another and more preferred joining option. The panel mat is configured to have a receptacle formed by a recess on the top of the panel mat. The receptacle is configured to receive removable panels that can be tiled together and are adapted to fit the shape and height of the receptacle. The receptacle can be formed by forming a first section to have a recess. By way of another example, the receptacle can be formed by providing four side pieces that are arranged to form a frame. The receptacle can have a bottom for receiving the removable panels (forming a bottom support) that is provided by forming the first section to have a recess and walls that form the frame or for example by the second section (and for example having the first section having walls that form the side walls of the receptacle).

The mats can have various sizes in a square of rectangular configuration typically ranging from 1′×1′ to 16′×16′ with rectangular sizes typically ranging from 1′×2′, 2′×6′, 3′×8′, 4′×8′, 4′×10′, 6′×9′, 6′×12′, 8′×12′, 8′×16″ and even 12′×16′. Larger sizes can be provided for certain specialty applications if desired. For manual installation, a square panel mat can have a 42″ side configuration as this facilitates molding of the first and second sections and results in a lightweight panel mat. The sections are typically molded to a thickness of between about 1/16″ to ⅕″ depending upon the plastic or elastomeric material that is used to make the panel. The panels themselves are slightly smaller than the overall size of the mat as they are configured and dimensioned to be received in the receptacle. The 42 inch square panel can have one or more replaceable panels as desired and would have a weight of approximately 40 pounds when molded from upper and lower halves of high density polyethylene each having a skin thickness of 0.2 inches. The preferred mats have sizes of 2.5′×2.5′, 3′×3′, 3.5′×3.5′ or 4′×4′ as these are relatively easy to be moved because they would have a weight of about 100 pounds or less so that they can be lifted and installed by manual labor rather than heavy equipment. The larger size panels are heavier but the temporary or permanent flooring can be installed more quickly given the greater area that these mats cover.

Rectangular mats can be used wherein the length dimension is double the size of the width dimension. Thus, along the length of one mat, two additional similarly configured mats would be joined thereto whereas the width dimension would be joined to half of the length of an adjacent mat. And if desired, combinations of square and rectangular mats can be joined together to form any particular shape decking or temporary roadway or walkway. As an example, a 42 inch square panel mat can also be joined to a rectangular panel mat that is 42″×7′ long. And if desired, rectangular or square mats can be made. The only limitation is the way that these mats are shipped with widths up to about 8 feet being preferred so that the mats can be shipped by conventional tractor trailers.

The thickness of the panel mats should be between about 1 and 3″ and typically between 1.5″ to 1.75″ thick. The mats (including the mats that use removable panels) are constructed to withstand repeated traffic from shop forklifts carrying loads, semi-truck and trailer travel, and stage point loads all while being rigid enough to protect the surface from damage and prevent any rutting of the subgrade. Point loads of between 300 and 500 psi are provided as point loadings while spread loadings of 40,000 to 50,000 pounds per square foot are provided. Particularly preferred materials for these panel mats are HDPE or Polypropylene. The panel mat should not have any external fasteners as the tabs and openings, slots or recesses are incorporated into the mat structure itself to facilitate interlocking during installation.

The panel mats and removable mats can be molded of many different materials, including any conventional polymeric or copolymeric thermoplastic materials, thermosetting materials, or even fiberboard materials made of recycled plastic or polymeric materials from used carpets, plastic packaging and the like. Mixtures or combined blends of plastic materials may also be used. The panels may also be made of elastomeric materials which can be thermosets (requiring vulcanization) or thermoplastic.

A wide range of thermoplastic or polymeric materials can be used for the sections of the panel mats and removable mats of this invention. These materials would be molded or cast to the desired size and thickness of the mat. Useful materials include:

-   -   Acrylonitrile butadiene styrene (ABS)     -   Acrylic (PMA)     -   Celluloid     -   Cellulose acetate     -   Cyclo olefin Copolymer (COC)     -   Ethylene-Vinyl Acetate (EVA)     -   Ethylene vinyl alcohol (EVOH)     -   Fluoroplastics (PTFE, alongside with FEP, PFA, CTFE, ECTFE,         ETFE)     -   Ionomers     -   Kydex, a trademarked acrylic/PVC alloy     -   Liquid Crystal Polymer (LCP)     -   Polyacetal (POM or Acetal)     -   Polyacrylates (Acrylic)     -   Polyacrylonitrile (PAN or Acrylonitrile)     -   Polyamide (PA or Nylon)     -   Polyamide-imide (PAI)     -   Polyaryletherketone (PAEK or Ketone)     -   Polybutadiene (PBD)     -   Polybutylene (PB)     -   Polybutylene terephthalate (PBT)     -   Polycaprolactone (PCI)     -   Polychlorotrifluoroethylene (PCTFE)     -   Polyethylene terephthalate (PET)     -   Polycyclohexylene dimethylene terephthalate (PC (PC) T)     -   Polycarbonate     -   Polyhydroxyalkanoates (PHAs)     -   Polyketone (PK)     -   Polyethylene (PE)     -   Polyetheretherketone (PEEK)     -   Polyetherketoneketone (PEKK)     -   Polyetherimide (PEI)     -   Polyethersulfone (PES)—see Polysulfone     -   Polyethylenechlorinates (PEC)     -   Polyimide (PI)     -   Polylactic acid (PLA)     -   Polymethylpentene (PMP)     -   Polyphenylene oxide (PPO)     -   Polyphenylene sulfide (PPS)     -   Polyphthalamide (PPA)     -   Polypropylene (PP)     -   Polystyrene (PS)     -   Polysulfone (PSU)     -   Polytrimethylene terephthalate (PTT)     -   Polyurethane (PU)     -   Polysulfone (PSU)     -   Polytrimethylene terephthalate (PTT)     -   Polyvinyl chloride (PVC)     -   Polyvinylidene chloride (PVDC)     -   Styrene-acrylonitrile (SAN)

It is also possible to utilize fiberboard as the elongated members or sheets that form the core structure. The fiberboard material is made of recycled plastic or polymeric materials from used carpets, plastic packaging, rice hulls and the like. They can be provided in the desired sizes for use as the core structure of the mats of this invention. They can be combined with other plastic materials as is generally known. In addition to being environmentally resistant due to their plastic content, these fiberboard/recycled materials are environmentally friendly by allowing recycling of used plastics or polymeric materials.

The top and bottom sections may also be made of an elastomeric material. The elastomers are usually thermosets (requiring vulcanization) but may also be thermoplastic. Typical elastomers include:

Unsaturated rubbers that can be cured by sulfur vulcanization—these are preferred from a strength and hardness standpoint:

-   -   Natural polyisoprene: cis-1,4-polyisoprene natural rubber and         trans-1,4 polyisoprene gutta-percha;     -   Synthetic polyisoprene;     -   Polybutadiene;     -   Chloroprene rubber, i.e., polychloroprene;     -   Butyl rubber (i.e., copolymer of isobutylene and isoprene)         including halogenated butyl rubbers (chloro butyl rubber; bromo         butyl rubber);     -   Styrene-butadiene Rubber (copolymer of styrene and butadiene);         and     -   Nitrile rubber (copolymer of butadiene and acrylonitrile).     -   Saturated (i.e., non-vulcanizable) rubbers include:     -   Ethylene propylene rubber (EPM);     -   Ethylene propylene diene rubber (EPDM);     -   Epichlorohydrin rubber;     -   Polyacrylic rubber;     -   Silicone rubber;     -   Fluorosilicone Rubber;     -   Fluoroelastomers;     -   Perfluoroelastomers;     -   Polyether block amides; and     -   Chlorosulfonated polyethylene.

The elastomeric, thermoplastic or thermosetting materials disclosed herein can also be provided with conventional fillers to increase weight and hardness. They also can be reinforced with particulates, fibers such as glass, fabric or metal screening or scrim to reduce elongation and provide greater rigidity.

Regarding the configuration of the panels, the sections are separately molded with peripheral boundaries that are configured to match each other. The first and second sections can be blow-molded or compression molded to the desired sizes. Then, the sections are joined together where the boundaries are in contact by welding, adhesives, heating, or interlocking connections or combinations thereof. It is desirable for the sections to be joined together to form a waterproof structure so that any openings existing between the sections do not fill up with dirt or water during use. Typically, the first and second sections are sealed by welding or adhesives at a peripheral seam. To facilitate an adhesive or weld the joint, the peripheral boundaries can be provided with a minimum flange detailed to provide additional surface area for sealing. The third section can then be joined to the other two to forma three ply mat. As noted, the third section provides additional compression and strength to the panel mat by holding the cells in position where they cannot move laterally.

The first section and removable panels can be configured with an appropriate top surface that may be relatively flat, textured or structured to facilitate movement over the panel mat. While a completely smooth top surface may be used, it is preferred that the top surface at least include some texture or channels that facilitate the drainage of moisture and provide a more secure footing for movement across the panels. The channels can be formed by texturing or spaced raised islands or other structures that are provided in the top surface. The top surface (first section and/or removable panel) can also include raised or embossed patterns or designs that indicate the supplier or owner of the mats. When a flat or relatively flat surface is provided for the top surface, grit or particles can be included to assist in providing better traction when the surface becomes wet. The panels are configured to be oriented with the top section (including removable panels) being the surface which is traversed by personal or equipment while the lower portion of the second section faces the ground.

The bottom surface of the panel mats may also configured with a flat, textured or structured surface. Preferably, the bottom surface is textured, structured or is provided with openings so that the panel mat can be securely placed on wet or muddy ground. For the latter feature, the bottom surface can be provided with closed holes that are of essentially the same configuration as the islands of the top section and that are sufficient tall to extend to the islands to provide further support to the upper surface of the top section. If desired, the holes can be configured as wells or cups that have the same configuration as the islands so that the top surfaces of the holes or cups fit into the islands. This provides reinforcement of the upper surface to movement or articles that contact that surface. If desired, the holes and islands can be joined together by welding, adhesives, bonding, heating or by snap-locking.

Alternatively, the first and second sections can be molded together as a single component. For this the top section is a plate or sheet that has a flat bottom surface so that it forms the upper portion and tops of the cells while the second section includes the cell sidewalls. The result is that the cells are closed at the top by the first section and the cell sidewalls provide the strength reinforcement of the top section. The first and second sections can be molded together to form the single component. The same result can be obtained by welding or adhering a top section plate that has a flat bottom to the upper ends of the cells of the second section. Of course the receptacle remains for receipt of the panels.

The third section can be provided as a flat plate if desired so that the bottom surface of the panel mat is relatively flat. Of course, the third section can also be provided with cells or can be in the form of a grating or other structure that has openings, channels or indentations. As the second section provides some of this, the third section is typically used to provide a flat bottom surface and to hold the cells of the second section in position between the first and third sections. And in some embodiments, the bottom surface can also include a textured surface or a raised or embossed patterns or designs that indicate the supplier or owner of the mats so that it appears the same as to top surface of the mat or to provide better gripping or more secure placement on the ground. Generally, the ground is prepared to be relatively flat to receive the bottom surfaces of the panel mats, but the panel mats can also be placed on a previously prepared flat cement or asphalt surface to provide temporary protection of such surfaces. Typically, however, the panel mats are placed on earth, grass, or similar terrain to provide better footing and support for personnel or light equipment traffic. The textured or structure bottom surface facilitate a more secure placement on gravel or wet or muddy ground.

An advantageous structure for the lower surface of the second section can be described as a honeycomb or open cell structure. The structures can be implemented in conjunction with removable panels if desired (e.g., by having them exist under the framing portion of the first section or inside the removable panels). The term “honeycomb structure” refers to a structure that has openings or open cells therein which extend to the bottom surface of the bottom section. The shape of the cells can be hexagonal, square, rectangular, or of another polygonal shape, or they can even be round or oval provided that the top surfaces or configurations of the cells match the configuration and arrangement of the islands of the top section. Some or all of the cells have a top surface which extend up to and into the islands through the lower surface of the top section. As noted, the top surfaces of these cells are joined to the lower surfaces of the islands by a press fit, snap-locking, adhesives or spot welding. The flat tops of the cells can also support a flat lower surface of the top section. With this construction, the strength of the panel can be further increased as each cell acts as a separate support for the upper surface of the top section.

Typically, the honeycomb pattern of geometrical cells includes those that have a top surface having a perimeter of 3 to 12 inches. This includes round top surfaces of about 1″ to about 4″ diameter and square or rectangular trapezoids having side of about 1″ to about 4″. As noted, the tops of the cells can be open or some or all of them can be closed. The same is true of the bottoms of the cells, which again can be open or where some or all of the cells terminate in closed flat surfaces. Similar perimeters would be provided for other shapes (i.e., oval, pentagonal, hexagonal, octagonal, etc.). For greater compressive strengths, more dense (i.e., smaller size) cells may be provided. A skilled artisan can design the cell configuration for any particular compressive strength requirements based on the overall size of the mat and number of sections that are to be included.

The sidewalls of the cells are also configured to impart strength to the mat. These are typically provided at an angle with regard to the top or bottom surfaces of the mat rather than being perpendicular. Angles of between 45 and 75 degrees are preferred with 60 to 65 degrees being optimal.

The panel mats are carefully designed so that they can interlock with adjacent, similarly sized and configured panel mats to form a temporary surface or substrate upon which people or light equipment can be placed thereon or moved across much like a building floor. This interlocking is achieved by the unique design of the sides of the mat. As noted, the first and second sides each include an upper structure that has an upper surface that extends the top surface of the mat and a lower surface that slopes downwardly towards the bottom surface of the mat, while the third and fourth sides each include a lower structure that has a lower surface that extends the bottom surface of the mat and an upper surface that slopes upwardly towards the top surface of the mat. The downwardly sloped lower surface of the upper structure and the upwardly sloped upper surface of the lower structure are configured to allow for overlapping with respective lower and upper structures of other like mats when placed adjacent thereto for joining therewith by which the overlapped upper and lower structures form a generally flat continuous top and bottom surface of the overlapped mats.

The upper and lower structures of the mats also include a plurality of openings. The openings of the upper structures are provided with a lower portion that protrudes below the sloping side while the openings of the lower structures are configured to be slightly wider and recessed then the protruding portions of the upper structures. Alternatively, the upper structures can be provided with downwardly facing protrusions while the lower structures can be provided with recesses that receive the protrusions. These configurations allow the protruding portions of the upper structures to be received within the openings of the lower structures so that a secure connection can be made. In some embodiments, the components are configured to provide snap blocking of the upper layer into the lower layer. This can be done by providing a narrower rim around the upper edge of the lower opening or recess. Alternatively, the openings can be designed to receive a fastening or pinning member, such as a cam, which can be inserted and rotated to lock the upper structures to the lower structures. This provides the most secure connection between the mats that is the least resistant to separate or move apart when in use. Details of these configurations are described herein in connection with the appended drawings.

These panels are designed for quick and easy installation by one or two workers. To do this, a first mat is installed in a particular position with the lower structures exposed in the direction for addition of further mats. Thereafter, the upper structures of the additional mats are placed above the lower structures of the previously placed mat to connect the subsequent mats to the initially placed one. These operations are repeated until the entire temporary floor structure is completed. And the ends of the initially placed mats that have upper structures which are not in contact with lower structures of adjacent mats, a separate board or configured component can be placed beneath those sections for support to prevent breaking of upper structures. Alternatively, a certain number of the mats that are to be installed can be provided with only the lower structures on two sides and with opposite sides that are have the thickness of the entire mat. Similarly, on the last mats to be installed, the lower structure would not be receiving the upper structure of an additional mat. Again, a separate component can be added onto the lower structure to form the remaining upper surface of the mat, or certain mats can be provided only with upper structures on two sides and with the other two sides configured to have the thickness of the entire mat.

The openings are aligned so that they can easily be connected together, either by the upper protrusion engaging the opening of the lower opening, with or without snap-locking, and without requiring a large amount of force to connect the structures together during installation or to disengage them when removing the installation. Alternatively, the holes can be configured to receive a fastening component that can be quickly placed therein and turned to lock the edges together.

The configuration of these mats as well as the various sizes that can be used, facilitates a relatively quick and efficient installation of a temporary flooring system. The smaller mats are easily lifted and installed by one or more workers without the use of any connecting hardware. The mats are designed such that each subsequent mat can be laid upon an installed mat with the sloping members in contact.

The openings can be configured so that those on the side of one mat can be received by or placed upon those on the corresponding side of another mat with the alignment tabs and slots assisting in the proper placement of one mat next to another. And when a very secure flooring is needed, the cams or other pinning elements can be used to connect the openings of those sides of the mats together in a locked position.

The configuration of the openings is designed and made either with cutouts or with a shorter or smaller dimension that does not extend to the full width of the mat such that the tabular members can be easily placed therein without binding. In addition, when larger panel mats are in use, the lifting elements allows those mats to be simply and easily transported into position. In fact, the flooring installation proceeds in a manner such that after the initial panels are in place, the equipment that is lifting the mats can then move over the previously installed mats such that the field or gymnasium surface is not damaged by the installation equipment.

As mentioned, the following description will first describe the general construction of panel mats followed by a description of the panel mat adapted to use and include removable panels in an area on the top surface of the panel mat.

Turning now to the drawings, FIG. 1 shows a square panel mat 100 that has a relatively flat upper surface 105 that has three openings 110 located on the periphery of two adjacent sides of the mat. These openings are actually provided on the upper structures 115 described previously that have a downward sloping bottom surface.

The opposite sides of the mat have the lower structures 120 that includes openings 125 and an upward sloping surface that is configured and dimension to conform precisely to the downward sloped surface of the upper structure.

And while these structures can have uniform descending or ascending flat surfaces, they are preferably made with different configurations such as undulations, or other irregular surfaces with the only requirement being that the upper structure and lower structure fit together to form a uniform thickness which is the same as that of the rest of the mat.

FIG. 2 illustrates the same mat 100 but viewed from its back side such that the same element numbers are utilized. FIG. 2 also shows a bottom plate 130 that is used to provide a smooth bottom to the mat when desired.

FIG. 3 more clearly shows that the panel mat 100 of FIG. 1 is initially molded in two sections, a first top section 200 and a second bottom section 300. The first section 200 includes the upper structures 115 and the second section 300 includes the lower structures 120. These sections are molded together to form an upper component for the mat. Alternatively, this upper component can be formed of a single molded sheet or plate and the appropriate configuration and structure can be provided by milling of the sheet or plate.

Joining technique for the first and second sections is to prepare them in a twin-sheeting operation. This operation, which is also known as twin sheet forming, combines the process disciplines of compression molding, blow molding, and vacuum forming to mold, laminate, and trim multiple layers of materials (substrates with cover stock) in a one step process. The twin sheet molding process forms two sheets of plastic simultaneously through the use of a separate mold on the top platen and a separate mold on the bottom platen. Once the plastic sheets have been vacuum formed, they remain in their respective molds. While both sheets still remain at their forming temperature, the two molds are brought together under high pressures and the two sheets are bonded together. The result is a single product with hollow areas requiring no secondary bonding operations.

Also illustrated in FIG. 3 are the cells 135 of the second section. These cells 135 are shown as trapezoidal pyramids having a flat top surface and four angled sides. The flat top surface contacts the lower surface of top section 105 providing numerous spaced sport supporting surfaces beneath top surface 105. And while these cells 135 are shown as pyramids, they also can be configured to be circular, oval, or polygonal in circumference with either straight sides or angled sides as shown. And in an alternate embodiment where the top surface 105 of the first section 200 is provided with a structured surface, such as raised circles ovals or polygons, the cells can be configured with the upper surfaces of the same shape as the raised structure so that the upper surfaces of the cells can fit in indentations on the lower surface of section 105. This also allows the first and second sections 200, 300 to join together when subjected to heat and pressure. Additionally, the upper surfaces of the cells can be configured with the recesses in the bottom surface of the first section 200 so that a snap locking fit can be achieved. When the first section 200 is adapted to receive removable panels the panel can be made without cells 135 or the cells can exist under areas outside of the receptacle for the removable panels.

FIG. 3 illustrates the angled sidewalls of the cells that provide additional strength to support the upper surface of the first section as well as to provide compression resistance to the mat. While it is possible to instead use 90 degree cell wall angles, as noted these are harder to mold into the second section and are not preferred for that reason. Instead, an angled sidewall, one that is fully or at least partially angled with respect to the upper and lower mat surfaces, provides greater rebound to the mat after the applied forces are removed. It also allows the cells to slightly compress but as each cell is adjacent another cell, the expansion is limited by the expansion of the adjacent cells. This provides good compression resistance to the mat. And a noted herein, the use of the bottom third section joined to the second section provides additional support for the cells and even more compression strength to the mat.

The aligned holes 110, 125 are also illustrated. These can be configured as described herein where the holes on the first section 200 can include a lower protrusion that fits within the opening 110 of the second section 300. Alternatively, the second section 300 can have a raised periphery around the opening which fits into a recess in the bottom of the opening 125 of the first section 200. The main feature of these holes are that they are in alignment to allow interlocking and connection of one mat to an adjacent, similarly configured mat.

Additionally, a third section 400 in the form of a flat plate is later added to the support component if desired when the flat bottom surface 130 is desired for the mat. FIGS. 3 and 4 also illustrate how the openings are not hindered by the addition of third section 400. Openings are provided in third section 400 either in the form of circular cut outs 140 or by removing a corner 145 of the plate. The third section 400 does not extend below upper structure 115 so that it does not interfere with the openings of the upper structure 115 of the mat. And as explained herein, third section 400 is an optional component which can be added to form a flat bottom surface 130 for the mat.

The third section preferably is used to provide a flat bottom surface for the panel mat. It is possible for the third section to be configured so that it also extends beneath the tabular members to further reinforce those members and help them resist damage during installation when the tabular members are inserted into the openings, slots or recesses, as well as to protect against damage from impact if the panel mats were to be dropped in a way where the tabular members would engage the ground first and bear the force of the weight of the mat. This is typically used on flat or graded surfaces, such as those provide by cement, asphalt or clay.

The first 200 and second 300 sections are joined together in a first operation either by compression molding or by heating and pressing the sections together. These sections also can be joined by suitable adhesives or by welding. Third section 400 can then be optionally added in a second operation where it is welded to the second section 300 of the joined first 200 and second 300 sections. The bottom surface 130 of the mat is selected based on the intended use of the mats.

FIG. 4 shows the bottom surface of the bottom section 300 of the panel mat 100 and the back sides 260 of the raised islands. As noted these cell openings provide better securement of the mat to the ground when the ground surface is wet or muddy. When the mat is to be used on a more uniform ground surface, such as a gym floor or paved parking lot, the third section 400 provides a bottom plate for the mat.

FIGS. 5 and 6 illustrate the first section 200 and second section 300 molded together as a single structure 250 prior to the addition of third section bottom plate 400. FIG. 6 illustrates the cell structure in a cross sectional view to show how each cell supports upper surface 105 of the top section. Such a configuration with multiple cells provides very good support for loads that are placed on upper surface 105 of the mat.

And while the cells are a preferred embodiment, it is also possible to configure the second section 300 with other structures that can support the first section 200 and upper surface 105 of the mat. Such other structures can include rod or bar members that are preferably rectangular and that are placed between and adhered to the first section 200 and second section 300 whether in the form of parallel spaced members or in the form of intersecting members that form a grid or grating-like structure that contacts the bottom of top surface 105 for support. The particular internal configuration between the first and second sections can be selected based on the anticipated weight and forces that the upper surface 105 of the mat will experience in use. And the formation of spacing between the bars or rods whether they are interconnected or not provide the equivalent of the cells of the current embodiment, with the top surfaces of the bars or rods providing the necessary support for the upper surface 105 of the mat. In embodiments having a receptacle for removable panels the panel mat can be adapted to include members outside of the area for the receptacle.

FIGS. 7 and 8 illustrate a second embodiment of a panel mat 500 according to the invention. This embodiment utilizes a similar structure for the upper and lower sections and bottom plate but is provided to illustrate further embodiments for locking the mats together. Mat 500 includes upper surface 505 and upper structure 515 that extend outside the core of the mat. Also provided are lower structures 520 that extend outside of the core of the mat. Upper structure 515 includes three openings 510 as shown. These openings align with openings 525 of lower structure 520.

FIGS. 7 and 8 also show tab members 530 that are present on the upper surface of lower structure 520 and that are used for alignment of the mats when the mats are to be connected together as described herein. The openings on the upper surface of the mat also include indicia 535A, 535B which are used to indicate whether the mats are in a locked position 535A or in an unlocked position 535B when the mats are joined together using a fastening element of a particular cam element. Openings 510, 525 also are provide a clear path extending through both openings and mats to cover the situation where a stake or other ground engaging component is used to secure the first mat in a particular position upon installation.

FIGS. 7 and 8 also illustrate that the openings 510, 525 are configured with an elongated slot which can facilitate entry of a fastening cam that can be used to join two adjacent mats together. As described herein in FIGS. 9-14, the fastening cam includes elongated tabular members that can fit into the slot of the holes and then be rotated to engage an internal structure of the holes to lock the mats together.

FIG. 9 is a side view of the mat 500 to illustrate the sloped portions of the upper 515 and lower 520 structures that contact each other from adjacent mats upon installation. The center portion of the mat is removed from FIG. 9 for convenience in illustrating these sloped portions of the upper 515 and lower 520 structures. Also shown are top surface 105 of the first section 200 and third section 400 bottom plate. The upper and lower structures each include a sloped surface that is configured for mating engagement with the other when adjacent mats are connected. Lower structure 520 includes tab members 530 as also shown in FIG. 7 which are configured in a line at the lower portion of the sloped section. An upper portion of the sloped surface includes an elongated slot 540. Similarly the lower surface of the upper structure 515 is also sloped and includes tab members 535 at an upper portion of the slope and elongated slot 545 at a lower portion of the slope. Tab members 535 of the upper structure are configured to fit into slot 540 of the lower structure 520 when an adjacent mat is to be connected. As the adjacent mat is lowered into position, tab members 530 of the lower structure 520 are received by slot 535 of the upper section thus allowing the upper structure 515 of one mat to be in contact with the lower structure 520 of the adjacent mat and forma uniformly thick surface for the joined mats. Tab members 530, 535 are utilized as they are more forgiving and allow lateral movement of the adjacent mat for installation with respect to the other mat, compared to the use of an elongated bar or rib member which fills in the slot and makes it is more difficult to adjust the position of the adjacent mat. In certain applications, however, a bar or rib rather than tab members would be sufficient and can be used as an alternate embodiment. Similarly, it is possible to use multiple separate openings that receive one or more of the tab members although this requires a more precise installation. Also, other arrangements of locating members where one is received in the other can be used instead of the tab members and slots or openings.

FIG. 10 illustrates a number of connected mats 600 that are joined together wherein one fastening cam 550 is illustrated. Each opening 510 that is positioned above an opening of an adjacent mat would be provided with a fastening cam 550 so that a sufficient interlocking arrangement is provided to avoid movement of one mat to another.

The mat 500 may have a flat upper surface 105 although it is possible to configure that surface with channels or other irregularities for water removal. For use indoors or in areas that are shielded from the elements (e.g., under a tent), a flat top surface is acceptable.

To provide a bottom flat surface 130 for the mat, third section 400 is provided as a separate flat plate. This plate 400 may be bonded to the lower side of the second section by welding, adhesives or by applying heat and pressure to the components in a mold. Third section 400 includes cut outs so that the openings of the upper and lower structures are not blocked.

As noted, although not necessarily preferred for certain embodiments, the panel mats can be formed of first and second sections that are obtained from a single piece of plastic or elastomeric material that is cut, drilled, milled or routered to the desired shape and configuration. For example, a solid sheet or molded plastic or rubber can be configured with the taps, slots, openings, and surface features described herein. While this is more expensive, the costs for setting up the machining equipment would be amortized across the large number of mats that would be produced with these features. This can be used to form the first and second sections of the mat while when a flat or closed bottom surface is desired, this would be achieved by the addition of a third section of a flat plate.

And as noted, the channels that are linear or random lines or grooves on the top and bottom surfaces of the panel mat allow water to drain from the top surface while also allowing the bottom surface of the mat to be more securely placed on wet or muddy ground. And the bottom surface may include openings as shown herein for the second to partially receive gravel or other prepared ground surfaces to again more securely anchor the panel mat in place. It also can be flat by the addition of a third section.

The mats can also be joined to form a temporary flooring installation that is continuous or discontinuous, i.e., one that leaves certain openings between joined mats. This allows the mats to be placed around trees, light towers or other obstacles that exist in the area that is to be provided with a temporary flooring of joined mats. In particular, it is relatively easy to leave openings such as by simply omitting one or more mats to provide open space in the floor structure. This can serve a number of purposes, such as allowing the floor structure to be installed around a column, pole, post or other upstanding structure, as well as to leave open space for a light tower, camera tower, and video screen support or speaker support tower. Furthermore, in the event that a mat is damaged after installation, it can be unlocked, disconnected and removed for replacement by another similarly sized and configured mat without having to remove all further mats that are connected together in the installation. Similarly, with use of the removable panels, in the event that a removable panel is damaged after installation, it can be unlocked, disconnected and removed for replacement by another removable panel without having to remove all further mats or panels that are connected together in the installation.

The top patterns or structures that are applied to the mats (and panels) also provide the capability to change out the center section to customize the mat with any particular design for a purchaser of the mat. This enables the costumer to advertise its company name or logo as well as to indicate the user or manufacturer of the mat. And furthermore, it is possible to add wraps, fabrics or coatings of a particular logo onto the upper surfaces of the mat. The logo can be applied to each mat or portions of a logo can be applied to different mats such that when they are connected, a much larger logo is made to provide enhanced visibility.

With reference now to FIG. 11, panel mat 1100 is illustrated to have a configuration including a receptacle 1102 for receiving removable panels of two types 1104 and 1106. Receptacle 1102 includes bottom surface 1108. The first section can have frame 1114 (that includes sidewalls as shown which are referenced as sidewalls 1110). Sidewalls 1110 and bottom surface 1108 together form a receptacle adapted to receive an array of removable tiles (that are attached together to form a working surface). As discussed above, the first section can be formed to provide frame 1114 including sidewalls 1110. The first section can also provide bottom surface 1108, or bottom surface 1108 can be provided by another member such as the second section. Receptacle 1102 can be adapted to have a shape that fits a group of removable panels when the removable panels are connected to each other (e.g., in a particular way to match the shape of the receptacle). Removable panels 1104 and 1106 are shown to have a particular physical shape and dimension but other shapes such as a square, rectangle, octagon, triangle, or others are contemplated. In the illustrated embodiment, two types of removable panels are illustrated that are configured (by repeating tiles) to be assembled together to fit receptacle 1102. The removable tiles can also be structured to only have one type of panel such as a square where each removable panel is made to have the same shape and size to provide modularity for removing and replacing panels. It is contemplated that multiple different types of panels can be used to form the working surface and fit the receptacle. In general, the removable panels are manufactured to have the same shape and size so that the same panel can be used to replace a damaged panel. Some small variation can be tolerated but the modularity relies on having removable panels that are substantially equivalent substitutes for a broken or damages removable panel. Illustrative examples of removable panels are described in U.S. Pat. No. 7,162,838, which is incorporated herein in its entirety. Also, other aspects of 1100 are described or understood from the description of panel mats herein.

With reference now to FIG. 12, an illustrative panel mat 1200 having assembled removable panels 1202 and 1204 is provided. As. Shown, a plurality of removable panels 1202 and a plurality of removable panels 1204 are attached to each other to form a working surface (that is generally continuous) that is sufficient for walking or for equipment or heavy vehicles to stand or roll over the surface. The arranged removable panels fit into the receptacle of mat 1200 and have dimensions such that height (depth) of the removable panels adapts the working surface formed by the removable panels to be even or continuous with the surface of frame 1206. Removable panels have mechanical connectors 1208 such as cams that connect and lock into place the removable panels into the array of removable panels that fit into the receptacle. Each removable panel can have a mechanical connector that cooperatively attaches to an adjacent removable panel to lock into place as a cam and hook arrangement.

With reference now to FIG. 13, an illustrative panel mat 1300 is provided that adapted to receive removable panels 1302 and 1304 that are configured to be at a different directional orientation than shown in FIG. 12. This embodiment also illustrates an implementation in which the frame for the array or panel of removable tiles is formed using four pieces that are fabricated and attached (e.g., bonded) to each other to form the frame. FIG. 14 illustrates panel 1300 with an assembled set of removable panels 1302 and 1304. Other aspects of panel 1300 are described or understood from the description of panel mats herein.

With reference now to FIG. 15, four frame sections for forming a frame are illustrated. As shown, a frame can be formed and attached to second and/or third sections using first frame section 1502, second frame section 1504, third frame section 1506, and fourth frame section 1508. The section as adapted to be structured to be the same as the relevant parts of the first section as described but with sidewalls 1510 that are form the sidewalls of the receptacle for receiving the removable tiles. Sections 1502 and 1506 have straight sidewalls, while, sections 1504 and 1508 have sidewalls that match a pattern that matches the removable tiles (repeating pattern of slanted and straight walls as shown). The frame sections have ends 1520 adapted to fit into each other to form the frame. The frame sections are bonded or fixed to each other to hold the frame in place. FIG. 16 illustrates the frame after the frame sections has ben fastened together. In some embodiments, the removable panels are first assembled in the configuration for fitting into the receptacle and then the frame sections are fastened around them (e.g., using known techniques). This traps the array of assembled removable panels in place in the panel. The direction force applied by the frame on the assembled removable panels establishes a tight fit sufficient to hold the removable panels in place without noticeable movement (e.g., slippage) when force is applied to a removable panel. FIG. 17 demonstrate an arrangement of multiple panels connected to teach other wherein each panel includes an array of removable panels that have been configured as an operating surface and removable so as to remove and replace individual panels.

To replace a damaged panel mat, the frame closest to the damaged mat must first be removed. Then, panels are removed from the removed frame area to the location where the damaged mat is located. Thereafter, the damaged mat is removed and replaced with a new panel mat. Finally, the remaining mats and frame are reinstalled to provide a renewed overall mat. This can be done in the field or back at the factory where the mats were initially made. Either way, most of the mat is re-used with only one or a small number of the panel mats becoming damaged to the point where replacement is needed.

Referring now to FIG. 18, there is shown a removable panel 1800 manufactured principally from a plastics material by a molding operation, the panel having a metal reinforcing element 19 (FIG. 2) embedded therein, in order to impart sufficient strength to the panel for its intended use. The panel 1800 can have a patterned upper surface 1812, to give the panel non-slip characteristics and various different patterns may be provided for this purpose. The panel is bound by several edges which are expressly configured to permit the panel to be connected to a plurality of like panels with the various edges interengaged and locked together. In order to form a continuous area of decking from an array of the panels, any one panel spaced from an edge of the continuous area will be interconnected with six like panels.

FIG. 18 illustrates an example of a removable panel 1800 (such as removable panel 1104 of FIG. 11). As shown, the structure has a shape comprising a sequence of shapes, from left to right, a rectangle, trapezoid, rectangle, trapezoid, and rectangle. The structure has approximately the same height or depth 1810 across the entire panel as shown. The arrangement of the trapezoids and the incline or slant of the sides 1820 of the trapezoid creates a narrowing effect in the middle of the panel. The shape is similar to the letter “I” but with the top and bottom connecting to the middle member 1850 at an angle. Removable panel 1800 includes holes 1840 for receiving a cam (or other mechanical connector) that can be twisted to lock panel 1800 to an adjacent panel having a hook in corresponding location. Removable panel 1800 includes hooks 1825 that are adapted to be inserted into adjacent holes when another mating panel is moved into position. Hooks 1825 are also used to lock the panel 1800 in place with a corresponding cams in an adjacent panel. As shown, panel 1800 includes recesses and protrusions on the sidewalls that are used to mate panel 1800 with an adjacent panel when the panels are being arranged and locked into place. This is an illustrative example and other configuration or arrangement are contemplated (e.g., fewer connectors or flat sidewalls).

Preferably, the removable panel comprises a plastics material moulding, with an internal frame of metal or some other sufficiently strong material embedded with that moulding. In this case, the internal frame may provide projecting tabs and receptors for the tabs of another like panel. Further, the internal frame may provide connection points for other components to be attached to the panel.

With reference now to FIG. 19, there is shown the metal insert 11 embedded within the removable panel, at the time of the moulding thereof. This example of an insert is pre-formed from metal strip, such as steel, in order to have the same shape as the panel when viewed in plan, but of a slightly smaller size such that the insert will lie adjacent the various edges of the panel, but will be covered with the plastics material to impart corrosion resistance to the insert. The insert is manufactured by welding together various strips pre-formed to have the required external shape, together with various reinforcing pieces internally within that shape. The parts 45 of the insert which will lie alongside the side edges 21,22 of the central section 13 carry the metal hooks 25 secured by a welding operation. The hooks on one side are oppositely directed compared to the hooks on the other side. Each further part 46, which will lie alongside a second edge 35,36 of the rectangular parts 18,19 has a slot 47 to permit the insertion therethrough of a hook 25 as the panels are fitted together. The locking members are disposed adjacent those slots 47, but internally of the insert, for interengagement with a hook inserted through the respective slot.

As shown in FIG. 19, the insert has four tubes 48 adjacent the corners of the central section 13 and arranged with their axes parallel and normal to the main area of the panel. These tubes may be used for the attachment of components to the panels, by drilling through the plastics material, or by blanking the plastics material from the tubes, during the moulding of a panel.

The insert may be made of other materials besides metal. For example, it might be moulded from a hard plastics material, or could be a carbon or glass fibre reinforced plastics moulding.

The removable panels of FIGS. 18 and 19 can be modified to be the shape of the second type of removable panel shown in FIG. 11 (panel 1106). It can be manufactured and be structured similar to panels of FIG. 18 or 19.

The panel mats themselves can be modified to fit any particular installation. A temporary floor installer would generally know how many mats are needed for a particular installation, as well as the width and length of the area to be protected by the temporary flooring, along with what types of openings may be needed to go around trees, poles, towers, etc. Thus, the installer can provide a kit with the requisite number and sizes of mats, adapters, half adapters, short adapters and side ramps and appropriate locking elements or cams so that the installer or purchaser would obtain everything needed for the installation. Generally, at least 3 cams are provided per mat to join the two upper structures to lower structures of an adjacent mat or to an adapter. One cam would be located in the corner opening of the mat, and one each would be located on the two adjacent sides. The lower structures on the other two sides of the mat are connected from the upper mat structure or side ramp that is placed above it, generally with two cams. Of course, more locking elements could be used depending upon the expected use of the temporary flooring system or to at least have a few spare locking elements in case some are damaged during installation. The kit could also include installation instructions showing how to start the laying and connecting of the mats.

The plastic and elastomeric materials disclosed herein generally have sufficient strength for many applications, but their strength and rigidity can be enhanced by reinforcing the material with appropriate fillers or other materials, such a glass fibers, other particular matter as is generally known in the art. The additional placement of a metal wire, bar, rod or plate into the mold that is used to prepare the sections or in between the sections before they are sealed together can provide further strengthening of the panel mats. Typical metals for such use would be steel, stainless steel or aluminum.

In some embodiments, the panel mats can be made translucent. When these panel mats are to be used outdoors and the mat materials are not sufficiently resistant to withstand long term exposure to sunlight, appropriate additives to improve the UV resistance of the material can be included.

The panel mats can be provided in different sizes, but generally, square mats or rectangular mats having longitudinal sides that are twice as long as the mat width are preferred. The thickness of the mat can vary depending upon the intended use of the mat. As noted herein, the thickness also determines the size of the side ramp angled portion. Also, the thickness is determined based on the thickness of each of the first, second and third sections. These can be varied as desired for the intended application, with thicker first and third sections and perpendicular cell walls in the second section being used for heavier load bearing installations.

The panel mats can be made with different materials and reinforcements for different applications. As the outer surfaces of the mats may be very similar in appearance, it is not readily observable as to which panel mat has a particular construction. For this reason, another aspect of the invention relates to the providing of each mat with identification means that indicates the material, reinforcement and construction of the panel mat. Thus, when a number of different panel mats are maintained in an inventory, the identification means enables operators to readily determine which mats have the particular materials and properties needed for a particular end use, so that the correct mats can be selected and provided to a jobsite for use by the customer. This would be necessary whether the mats are being purchased by the customer or whether the mats are being leased for use.

Therefore, in sum, it is to be realized that the optimum dimensional relationships for the parts of the invention can include variations and tolerances in size, materials, shape, form, function and use are deemed readily apparent and obvious to the skilled artisan, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the claims appended hereto.

Unless defined otherwise, all technical and scientific terms used herein have same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Also, as used herein and in the appended claims, the singular form “a”, “and”, and “the” include plural referents unless the context clearly dictates otherwise. All technical and scientific terms used herein have the same meaning.

The foregoing detailed description is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily be apparent to those having ordinary skill in the art, it is not desired to limit the invention to the exact constructions demonstrated. Accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention. 

What is claimed is:
 1. A lightweight universal panel mat made of plastic or elastomeric material and designed to be interlocked with additional panel mats of similar configurations, comprising: a first section having an upper surface that forms a peripheral top surface of the panel mat and is relatively flat and provides a receptacle that is adapted to receive one or more removeable panels; a second section having geometry that supports the first section; first, second, third and fourth sides forming a perimeter of the mat, wherein: the first and second sides are adjacent and each includes an upper structure that has an upper surface that extends the top surface of the mat and a lower surface that slopes downwardly towards the bottom surface of the mat; the third and fourth sides are adjacent and each includes a lower structure that has a lower surface that extends the bottom surface of the mat and an upper surface that slopes upwardly towards the top surface of the mat; each upper and lower structure includes at least one opening passing therethrough; wherein the downwardly sloped lower surface of the upper structure and the upwardly sloped upper surface of the lower structure are configured to allow for overlapping with respective lower and upper structures of other like mats when placed adjacent thereto for joining therewith by which the overlapped upper and lower structures form a generally flat continuous top and bottom surface of the overlapped mats; and wherein the first and second sections are welded or bonded together to form a unitary panel mat.
 2. The mat of claim 1 further comprising one or a plurality of removable panels received in the receptacle wherein the panels have upper surfaces that conform to the top surface of the mat and the first and second sections form a frame around a plurality of the removable panels.
 3. The mat of claim 2, wherein the first section comprises four sections that are attached together and form a frame that shapes sidewalls for the receptacle.
 4. The mat of claim 3, wherein the panels are locked to each other to thereby form a working surface and the panels are removable from the working structure to be replaced if damaged.
 5. The mat of claim 3, wherein the sidewalls of the receptacle include protrusions or recesses for joining with mating recesses or protrusions of the removable panels so that the panels can be locked to and secured to the sidewalls of the receptacle or to each other.
 6. The mat of claim 2, wherein the panels have a uniform configuration to facilitate removal and replacement of damaged panels.
 7. The mat of claim 2, wherein the panels are removable panels of at least two different types that interengage.
 8. The mat of claim 2, wherein removable panels have rectangular or square shape and a plurality of apertures that are configured to align with adjacent similarly configured panels.
 9. The mat of claim 8, wherein the one or more panels comprises an array of removable panels wherein each removable panel comprises a cam that connects to an adjacent removable panel.
 10. The mat of claim 2, wherein each removable panel comprises a cam and a hook that engages a cam of an adjacent panel when locked.
 11. The mat of claim 2, wherein each removable panel comprises a protrusion and recess that mates with a recess and protrusion of an adjacent panel when locked.
 12. A support surface, deck, walkway or roadway comprising the mat of claim 1 that further includes an array of removable panels locked to each other and positioned in the receptacle of the mat.
 13. The invention of claim 12, wherein the second section includes cells under the first section in an area that forms a frame for the removable panels.
 14. A support surface, deck, walkway or roadway comprising a plurality of the mats of claim 12 that are attached each other wherein the panels are removable when damaged and are replaced by a like configured the service panel to extend life of the support surface, deck, walkway or roadway.
 15. A method of extending the service life of a support surface, deck, walkway or roadway which comprises: constructing the support surface, deck, walkway or roadway with a plurality of mats according to claim 2; and replacing any of the removable panels that become damaged to allow continued use of the support surface, deck, walkway or roadway without having to replace an entire mat.
 17. A method of extending the service life of a support surface, deck, walkway or roadway which comprises: constructing the support surface, deck, walkway or roadway with a mat according to claim 2; and replacing any of the removable panels that become damaged to allow continued use of the support surface, deck, walkway or roadway without having to replace an entire mat. 